There is a freight vehicle (hereinafter referred to as a cab-over truck) in which a cabin (hereinafter referred to as a cab) is placed in a front portion of a chassis frame while a driver's seat is positioned generally above an engine. In such a cab-over truck, the cab is tiltably supported by the chassis frame so that an engine room can be opened to perform maintenance on the engine, and the like.
The chassis frame includes: a pair of side members disposed on both sides in the vehicle width direction and extending in the front-rear direction of the vehicle; and multiple cross members extending in the vehicle width direction so as to connect the pair of side members to each other. The cab is mounted on the chassis frame through cab mounts provided on four front, rear, right and left corners of the cab. The two front cab mounts of the cab are connected to a pair of cab mount brackets that are fixed to a front end side of an upper surface of the side members. Thus, a front portion of the cab is tiltably supported by the chassis frame.
There are various kinds of front collisions of the vehicle. In some cases, a vehicle may collide with a collided object having substantially the same height as that of the cab mount brackets (for example, a rear end of the chassis frame of a vehicle in front, and the like). In this case, a collision load toward the rear of the vehicle is applied to the cab mount brackets fixed on the side members. For this reason, an upward moment acts on front end portions of the side members. Thus, of the side members, portions where the cab mount brackets are fixed are bent and deformed.
For the purpose of preventing deformation or damage of the side members due to such a load applied to the cab mount brackets, Japanese Patent Application Publication No. Hei 10-316013 discloses a structure in which sub-frames are attached on side members while cab mount brackets are fixed to the sub-frames, so that energy is absorbed by deforming the sub-frames.
Patent Document 1: Japanese Patent Application Publication No. Hei 10-316013